Savannah lwIP up to 2.2.1 SMTP Client buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.6$0-$5k5.02

Summaryinfo

A vulnerability was found in Savannah lwIP up to 2.2.1. It has been classified as very critical. Affected is an unknown function of the component SMTP Client. The manipulation leads to buffer overflow. This vulnerability is documented as CVE-2026-15340. The attack can be initiated remotely. There is not any exploit available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability was found in Savannah lwIP up to 2.2.1 and classified as very critical. This issue affects an unknown code block of the component SMTP Client. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

lwIP SMTP client does not check the size of inputs, potentially allowing a buffer overflow.

It is possible to read the advisory at cisa.gov. The identification of this vulnerability is CVE-2026-15340 since 07/09/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/09/2026).

Applying the patch patch_125_smtp_txbuf.diff is able to eliminate this problem.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.6

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.8
CNA Vector (icscert): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: patch_125_smtp_txbuf.diff

Timelineinfo

07/09/2026 CVE reserved
10/09/2026 +92 days Advisory disclosed
10/09/2026 +0 days VulDB entry created
10/09/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: cisa.gov
Status: Confirmed

CVE: CVE-2026-15340 (🔒)
GCVE (CVE): GCVE-0-2026-15340
GCVE (VulDB): GCVE-100-415931

Entryinfo

Created: 10/09/2026 17:08
Changes: 10/09/2026 17:08 (75)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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